A Study On Security And Anonymity Of Structured Peer-to-Peer Networks

The development of Peer-to-Peer network has experienced three revolutions until now. Structured Peer-to-Peer network has become the future trend of development, because it provides high performance and correctness for efficient distributed lookup service. Unfortunately, as structured Peer-to-Peer network is deployed widely, secure defects of it have been gradually exposed, which prevent it from being used in the systems requiring higher security and anonymity. Therefore, security and anonymity issues of Peer-to-Peer begin to be focused on by researchers.This thesis discusses and analyzes common attacks and privacy exposure issues on structured Peer-to-Peer network, and presents corresponding secure and anonymous countermeasures. In the design part, two secure and anonymous models are built, by introducing Public Key Cryptography and Identity-Based Encryption. In the models, the reliability, confidentiality and integrity of messages and data are guaranteed by using authentication, encryption and signature techniques. Furthermore, three new and practical security mechanisms are proposed: (1) a verifiable way of generating node ID, to limit free generation of node IDs and cut off the first phase of many common attacks on structured Peer-to-Peer; (2) a verification session for routing table updates, to prevent malicious routing table updates from making node store incorrect routing information, causing routing table pollution and reducing the efficiency of the network; (3) an approach to detecting deception in forwarding, to detect dishonest behaviors in forwarding routing messages, and stop malicious node from forwarding routing messages to incorrect nodes. In addition, in order to enhance the anonymity of the system, instead of the iterative version, which could expose the identity of requesters and recipients in a lookup procedure, a recursive version of key lookup procedure in secure tunnel is presented.Finally, designs in the thesis are evaluated, analyzed and simulated. The results demonstrate that the presented mechanisms can make structured Peer-to-Peer network more robust and secure, without reducing lookup efficiency significantly.